EF-S 17-55 F/2.8 USM IS vs. EF 24-70 F/2.8L USM - Please Help !

Hey guys,


I want to choose a relatively wide-zoom for my Canon 7D.
I was thinking between the EF-S 17-55 F/2.8 USM IS to the EF 24-70 F/2.8L USM


I have read the reviews here onwww.The-Digital-Picture.com Bryan praises the EF-S 17-55 as being an excellent very sharp lens which the author says have out performed many L series zoom lenses.


However the site's ISO 12233 Chart 100% crops show this lens to be a far cry from being sharp. Compared to the EF 24-70 the EF-S 17-55 looks dull, definintely not as sharp.


Check this out:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?CameraComp=0&FLIComp=0&APIComp= 0&Lens=398&Camera=474&Sample=0&FLI =0&API=0&LensComp=101
It shows the 17-55 crop and when you mouse over the image you'll get the 24-70 crop.


This shows the 24-70 to be much sharper and contradicts what the reviewer wrote about the lens. So I am totaly confused. It seems the review contradicts the ISO 12233 Crops.


If I had a full frame, the 24-70 would have been ideal. But since I have the 7D cropped 1.6x sensor it acts like 38-112 (35mm equivalent). Which is not that wide at all. So that brought me to the decision to get the EF-S 17-55 which would be like 27-88mm (on 7D) which is an excellent range. But range aside, if the 24-70 is so much sharper than the EF-S 17-55 plus an L series (althogh the EF-S 17-55 is pretty much like L series).


So money aside, which would you get ? Taking into consideration focal range and performance.


Would greatly ppreciate some educated replies by you guys. Need to make a choice in the next 48 hours cause have an option to buy cheaper overseas.


Thanks

Had the same decision to make about a year ago. I went the 24-70mm route. Both are excellent piece of glass, but it all comes down to the shooting style you like and flexibility you want. I got a Sigma 10-20 that coves the wide end and I use my 24-70 primarily between the 45 and 70mm range.


Are you considering going full frame/APC-H in the near future?


As I said, you can't go wrong with either of the two.


Joël

I haven't used either lens, but I will say that your link is not a good comparison which may be why you're a bit confused over what the review says.


These are 100% crops from camera of very different resolutions and sensor sizes. You really need to compare a lens on the same camera to get a fair comparison, but that option isn't available for teh 24-70 and 17-55 since the 24-70 was only tested on FF.


To illustrate my point, check out how the 70-300 tests against itself on the 40D and 1Ds MkIII


http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=358&Camera=453&Sample=0&am p;FLI=4&API=1&LensComp=358&CameraComp= 452&SampleComp=0&FLIComp=4&APIComp=0


Crop cameras, especially the 7D have much higher pixel densities and so are more demanding on a lens at 100%. This is part of why full frame images can be so much sharper, because there is so much more space (and glass) feeding each pixel even at high resolutions.


As a side note, see the following quote about the accuracy of the ISO charts here: http://www.the-digital-picture.com/Help/ISO-12233.aspx


"For the most part, I find the results to be very indicative of the image quality of the lens being tested and
the comparisons work very well - the results are even better than I had hoped for.
However, I'm not totally satisfied with the Canon EF-S 17-55mm f/2.8 IS USM Lens
results - the 17-55 under-performed in the comparison tool images in my opinion"



Back to your lens choice briefly, I used a 24-105 on my 40D and I would not have been happy if that was my widest lens. I also had a 10-22 which I used for landscapes and even indoor sometimes.

I want to add one thing to make sure that I didn't confuse the subject. Don't think that because the 70-300 charts look better on the IDsIII that somehow the lens changes when used on FF, it is simply that the IDsIII is less demanding because the pixel density is so much lower.


Compare the IDsII vs. IDsIII


http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=358&Camera=9&Sample=0& FLI=5&API=1&LensComp=358&CameraComp=45 3&SampleComp=0&FLIComp=4&APIComp=0


The IDsII looks clearly even much better than the IDsIII. This isn't because the IDsII is a superior camera, obviously that is not the case. Again the pixel density has gotten even lower (same sensor size but lower resolution than IDsIII) so at 100% you're looking at less detail and therefore less of the faults of the lens. That is why this is a test case for comparing lenses, not cameras :)

Compare them at the same focal length. Unfortunately they aren't available on the same camera.

Quote:

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Originally Posted by PhotoMaxi

However the site's ISO 12233 Chart 100% crops show this lens to be a far cry from being sharp.

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<meta content="text/html; charset=utf-8" http-equiv="content-type" />
StapledPhoto already explained why that is incorrect, so I wont go into it. Here is a site that has reviewed both lenses on the same camera:



<meta content="text/html; charset=utf-8" http-equiv="content-type" />
http://www.photozone.de/canon-eos/184-canon-ef-24-70mm-f28-usm-l-test-report--review?start=1



<meta content="text/html; charset=utf-8" http-equiv="content-type" />
http://www.photozone.de/canon-eos/178-canon-ef-s-17-55mm-f28-usm-is-test-report--review?start=1


It shows that the 17-55 is noticeably sharper in the center as well as the corners at all overlapping focal lengths at f/2.8. At f/4 their performance is closer together.

Also something to note, although your lens looks worse with more megapixels your print will look sharper. Your lens resolution does not change because your have more megapixels, you just magnify your lens flaw at 100%.


John.